I hate counting calories. If it works for you, do it, but it just doesn't seem natural to me. I really don't want to get into any debates about calorie counting because I know that that's the route most of you take. But I decided to give you some information on how many calories you're actually burning when you exercise.
I have a stationary bike and an elliptical trainer at home, both made by Tunturi. If you're a short person, I highly recommend this brand. At 4'10", these machines fit me to a T. And like all exercise equipment, my bike and elliptical tell me how many calories I've burned. Or do they?
I can't remember where I read this, but the calorie read-out that you get from your exercise equipment is VERY, VERY approximate. The machine is calibrated to calculate how much an average man who weighs--I don't know--let's say 150 pounds or so would burn. When I read bloggers who say that the 30 minutes on the bike netted them x calories burned, I just have to wonder...because most (if not all of them) aren't 150-pound men.
If you MUST know how many calories you've burned during your work-out, try this site: http://www.fitwatch.com/database/searchexdb.html and compare it to what the machine said. If you're using a super-duper machine that lets you input your weight, the calculation will probably be much more accurate. If not, the information that you get could just be a load of hooey.
Just as an example, according to the fitwatch tracker, a 130-pound person will burn 341 calories using the elliptical trainer at a moderate pace for 30 minutes, while a 200-pound person will burn 524 calories. Furthermore, muscle cells burn more calories than fat cells and men are more muscular than women--even fat men.
So exercise because you want to, because you feel better when you do and because you know it's good for you. Just don't believe the calorie counter.